Vehicle suspensions generally incorporate shock absorbers or dampers to dampen or “smooth” the effects of road surface imperfections, such as bumps and potholes, on the vehicle's ride. For example, known “coil-over” shock absorber suspension systems typically deploy a coil spring about the cylinder body and telescoping damper rod of a fluid-type shock absorber, such that one end of the spring is seated about the cylinder body and the other end of the coil spring is seated on an upper mount assembly that is itself captured atop the spring, for example, by a fastener secured to the end of the damper rod. The upper mount assembly is, in turn, mounted to the vehicle's frame, which may include a suspension tower specially adapted to receive and support the upper mount assembly. A separate jounce bumper, typically formed of a relatively soft material such as microcellular urethane or the like, is disposed about the damper rod below the upper mount assembly to provide relatively-gradual energy dissipation if the suspension “bottoms out,” i.e., if a wheel impact substantially or completely compresses the spring such that the upper end of the cylinder body engages the upper mount assembly.
Although coil-over-shock absorber suspension systems may be provided as part of a vehicle's original equipment, it is often desired to modify vehicles so as to provide for “air-over” vehicle suspension assemblies, in which the coil springs of such coil-over suspension systems is replaced by an air spring. Such air-over vehicle suspension systems advantageously permit the vehicle operator to readily adjust the relative inflation of the air spring to thereby adjust such suspension parameters as the vehicle's nominal ride height and the spring's nominal spring rate. Further, when used in combination with an on-board source of pressurized air, such air-over vehicle suspension systems advantageously permit the vehicle operator to vary such suspension parameters in real time. Unfortunately, when the vehicle is operated with a reduced ride height, known separate jounce bumpers may not be employed, because the reduced ride height may itself cause engagement of the cylinder body with the jounce bumper, with an attendant increase in vehicle noise, vibration, and harshness.